I choose "other", I think Litecoin will be the best for us to be exchanged for BTCUI and other currencies. Because it have very low transaction fee, soon a lot of people will aquire it (because more and more people will using it for paiement), I don't know much exchange pairing with LTC.
So the withdraw won't have much

My 2nd choice will be BTCUI because it's our token using it to lower the fee of the exchange (like the Binance's BNB), and it could get interesting to see the price rising, but I think it will be more an "utility" token than a paiement system

Ethereum itself is our best bet and easiest being btcui is based on erc20. I would like to see btcui and eth to be interchangeable. Eth is second most popular crypto, and my cryptocurrency of choice next to btcui.

i know most of us choose ltc but i choose btcui. because when we pair with a small price's coin,there will be more pump and dump. and the new trader like me get a good profit. coz they can exchange their coin twice or three times on a day. and it's transaction fees is also lower than other. so i suggest that make it pair for btcui exchanger.